PV solar panels are an important source of electrical power. A typical PV panel is organized as a series connection of individual PV cells. A common configuration is 72 PV cells per panel. A typical PV cell operating voltage under full illumination is approximately 0.7 V. An illuminated PV panel with 72 Direct Current (DC) PV cells will therefore have an open circuit output voltage of approximately 50 volts DC. PV panels are typically serially connected to form a “panel string”. In a DC PV panel system, the output of the panel string could connect to an inverter which converts the DC power of the PV panels into Alternating Current (AC) power suitable for an electrical grid. Typically, there are between five and twenty PV panels in a panel string producing a combined string DC voltage in the hundreds of volts.
PV panels produce power whenever they are illuminated. The voltages on a panel string could reach hazardous levels and constitute a safety hazard since the PV panels continue to generate voltage even when the PV system is disconnected from the electrical grid.